A job is a job, but there is something special about working on the Olympics, Jack tells me. "I mean bloody hell, we're building the Olympics. You only get to do that once in a generation."

But just who is building the Olympics? According to stories in the Daily Mail and the Daily Telegraph, the chief beneficiaries have been Polish carpenters and illegal migrants. "Those stories," he says, wearied, "are not even half true."

Workers on the Olympic site are banned from public pronouncements, so Jack, as we will call him, is keen not to be caught speaking out of turn. But he is keen to talk about the international effort that is transforming this long-neglected corner of east London.

The notion of a foreign takeover is nonsense, he says. Latest figures say 78% of the workers "inside the fence" are British. That's not to say they all look like Churchill. "I have friends there with origins in India, Romania, Sri Lanka. From all over. One of my friends from India speaks better English than me."

And what of the others? Well, there's the Irish, the largest non-British group, but also Romanians, Lithuanians, Poles, Aussies, Bulgarians, Ghanaians, Nigerians. Many of the security guards are former Gurkhas, he says. "Lovely guys. They are the first faces you see."

As an activist with the construction union UCATT, particular things make Jack proud of what's happening inside the fence: the way workers from different countries are obliged to mingle during training periods; the workmate interpreter system that assists those who don't speak fluent English; the on-site classes for those who want to learn. The variety of food produced by the African and Romanian chefs. The pulling together. "On the Terminal 5 project, I remember tension between Indians and Pakistanis at certain points," he says. "Not here."

Nothing is perfect, says Jack, but there is pride that for all the knitting together of different types, the stadium project has not yet resulted in a single death. Sydney had one; Athens many.

It's punishing work. Maybe that helps. "If you are digging a hole with a Jamaican in the middle of a thunderstorm," he says, "by the time you're finished, he's your mate."